The present invention relates to air purifying devices, and in particular to such devices which both filter and neutralize odors in the air.
In hospitals and many other enclosed areas, it is desirable to provide an air purifying system which removes both particulate matter and odors which are molecular in nature. Many air circulation systems are in use in which filters are interposed in the flow path of an air stream to remove particulate matter, but filters are unable to remove molecular odors. Certain large filtration systems employ charcoal filters interposed in the flow path to remove molecular odors, but such systems are quite expensive, require frequent maintenance, and are impractical in many applications.
Various chemicals have been developed which neutralize molecular odors. Such chemicals are usually placed in fixed containers having small apertures so that air slowly moves through the containers by natural convection. Such chemicals have their own unpleasant odor, and cannot simply be interposed in a moving current of air provided by an active air circulation system because the odor caused by the chemical vapors would be overpowering.
A recent attempt has been made to incorporate an odor neutralizing chemical in an active air circulation system. This device is called the "Ecologizer" and is produced by Rush-Hampton Industries in Longwood, Florida. In this device, a crystal odor neutralizing chemical is located in the center of a duct through which air is forced by a fan. Most of the air propelled by the fan flows around the crystal so that only a relatively small amount of the crystal vaporizes and enters the air stream. Unfortunately, this device provides no filtration of particulate matter, and provides little control over the amount of odor neutralizing chemical vaporized so that either too much or too little of the odor neutralizing vapors are entrained in the air stream.